Pheromone traps

I'm trying to find a supplier for pheromone traps. I am particularly interested in lilac/ash borer, peach borer and possibly other tree insects. I appreciate any information you can furnish. — Colorado

Two suppliers are Scentry Biologicals (800-735-5323; and Trece (; 831-758-0204). Check out their web sites, which provide extensive lists of pests for which they offer pheromone lures, including those you mentioned.

Alternately, you can try Gempler's, which carries products from both of these companies (; 800-382-8473).

One born every minute

I have a property with many trees producing suckers from the roots close to the base of the trees. I have tried everything I know to fix the problem. Can you tell me what causes the problem and how I might fix it? — Idaho

You basically have two options: physical removal and chemical treatment with a PGR.

Physical removal involves a great deal of labor if, as you say, you're dealing with a large number of trees. But if that's your choice, then at least try to remove the suckers while they're still young. They often can simply be rubbed or pulled off by hand while they're still soft and succulent. For one or a few trees, the manual option is probably the most practical.

The other option is to use a growth regulator with naphthalene acetic acid (NAA). Two brands I'm aware of are Sucker Stopper from Monterey Chemical and Tre-Hold from Amvac. NAA is an effective treatment that orchard growers have used for many years. It is fairly effective and more cost-efficient than hand labor for large numbers of trees.

NAA is registered for some of the more troublesome ornamental species, including crabapples, pears and olives, and its label language seems to allow treatment of other species not specifically listed. However, you will definitely want to use a small test spray to ensure safety on species not listed.

Roots close to or at the soil surface tend to sucker more. The problem also may be exacerbated by injuries, such as from mowers. Encourage deeper rooting with loose, well-aerated soil conditions and deep watering as much as possible.

However, some species tend to sucker naturally and such specimens are probably going to do it no matter what. For example, apples, plums and pears, olives, honeylocust and ailanthus, among many others, sucker prolifically.

Oil storage

Owner's manual recommendations give either hours or months for oil-change intervals. Do I still need to change my oil every 3 months even if the hours are low? — Michigan

Most commercial mowers have hour meters, and oil-change recommendations are typically based on hours, not elapsed weeks or months, so this is fairly straightforward. (Even equipment without hour meters still often recommend oil changes based on hours.)

However, on-road vehicles usually give a months-or-miles oil change interval. Because of the variable nature of on-road driving, it's fairly easy for miles to remain low, while engine wear is high, such as with stop-and-go city driving. The time interval helps provide some insurance against such conditions.

One situation where you can ignore time intervals is when equipment or vehicles are put into storage. But be sure to put fresh oil into the engine before storage. Robert Sokol, an engine specialist with Intertec Technical Manuals, explains that oils contain additives such as detergents that help fight contaminants. There is a limited supply of these additives in oil, and when they are used up, as with dirty oil, the oil loses its ability to protect engine parts, even when engines are sitting idle. (Used oil can become acidic, causing corrosion of metal parts.)

However, fresh oil sitting idle — such as in stored equipment — will not deteriorate. That's why Sokol recommends an oil change before putting equipment in storage. This not only provides good protection during storage, but avoids another problem that Sokol sees periodically. Often, people neglect oil changes in the fall, thinking they'll have time to get to it in the spring. Then they forget to do so in the rush of business when mowing begins again. This is doubly bad, because not only has the engine sat all winter with old oil, it then undergoes additional wear as the engine is run with dirty oil mixed with water condensation that may have accumulated during storage.

Eric Liskey has a bachelor's degree in ornamental horticulture and a master's degree in botany. He has been licensed for pesticide advising and applications in California and Missouri, and has more than 10 years combined professional experience in landscape installation and maintenance, nursery retailing, pest management and botany.

If you have a question about landscape or turf management, write to “Researching Maintenance,” Grounds Maintenance, P.O. Box 12901, Overland Park, KS 66282-2901, or send your question by e-mail to

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